Multiple sensing circuits combining fire detection and intrusion detection circuits, for example, are well known. Examples in the patent literature include U.S. patents to Rowe et al., U.S. Pat. Nos. 2,640,975, Hoey, 3,150,359, Midkiff, 3,487,404, Hough, 3,603,973, Benedict, 3,678,511, Judlowe, 3,686,654, Durkee, 3,686,668, Schubert, 3,810,171, Schmitz et al., 3,990,075 and Wise, 4,001,819.
The devices of the prior art have been either limited in the numbers of sensing functions they could perform, or extremely complicated, or both.
One of the objects of this invention is to provide an electronic sensor package which provide options for at least six different sensor functions in a compact package, that is economical to produce, rugged and reliable.
Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.